Shimano XTR FH-M9111 Rear Hub U 28h

Size: Unisex 28h

Color: Stealth Gray

Retail Cost: $289.99

For over two decades Shimano's XTR group has proven itself at elite levels of mountain biking as a trustworthy option for riders and racers who refuse to compromise on their equipment. The all new XTR FH-M9111 Rear Hub continues the winning pedigree, and is a perfect complement to the rest of your XTR M9100 group. Made with precision using the lightest and strongest materials Shimano can find, their flagship rear hub offers impressive stiffness, low-rolling resistance, and the longevity you've come to expect from XTR—all at a very low weight. It's compatible with XTR 12-speed Micro Spline cassettes, and uses a new ratchet drive system that delivers an impressive 7-degrees between engagement points.

For the XTR M9100 group and the XTR rear hub, Shimano designed a new freehub system called Micro Spline. Micro Spline allowed them to move from an 11t to a 10t small cog on their cassettes while adding a 12th gear, increasing the gear range to a whopping 510% on their wide-range 12-speed cassette. The Micro Spline freehub body is made of aluminum instead of steel in order to save weight, but is claimed to be more durable thanks to an increased number of splines that distributes pedaling forces more evenly over a greater area, preventing the cassette from eating into the freehub body. The design also allows for larger-diameter axles inside the hub for a boost of stiffness when you're charging across rough terrain.

Shimano also changed their drive mechanism, omitting the traditional pawl system in favor of a system that uses two ratcheting driver plates. These plates glide across each other with minimal friction when coasting, but engage rapidly when force is applied to the pedals. The system offers an impressive 7-degrees between engagement points, and prioritizes reliability above all else.

Finally, the XTR rear hub uses cup and cone bearings that are serviceable. That's definitely something you'll want to do on occasion in order to keep them running in top shape. After all, they're a lightweight, race-tuned set of bearings, which means they're capable of operating at levels that other bearings can only dream of.